Merck sets clock for sleep drug submission

Merck teased a bit more information about its prospective sleep drug Suvorexant at the Meeting of the Associated Professional Sleep Societies in Boston Wednesday. The presentation, which was also webcast, ran over similar ground as it did in November 2011, but with some additional safety/efficacy information. Merck said in a statement that it plans to file an NDA in 2012 or 2013.

The clinical trial data discussed Wednesday showed that the drug, which targets orexin receptors helped patients fall asleep more quickly and to stay asleep. The company said patients did not develop a tolerance to the drug or experience withdrawal headaches if during a yearlong study. A spokesperson said results also indicated that patients did not pack on a meaningful amount of weight compared to placebo. This could be an edge, since competition has been linked to food binges.

Approval would make Suvorexant the first orexin receptor antagonist on the market. The drug differs from offerings like Lunesta (eszopiclone) and Ambien (zolpidem tartrate) because it targets receptors related to wakefulness, as opposed to GABA receptors, which influence sleepiness. Merck said part of this mechanism's appeal is that it seeks out a more refined target: instead of pursuing GABA receptors, which are spread throughout the central nervous system, Suvorexant's targets are concentrated in the hypothalamus.

Tapping into the sleep category could mean access to a massive market, but one that is flooded with generics: Americans spent $2.8 billion on generic Ambien last year, according to Wolters Kluwer. The company said Wednesday it was premature to talk about payers putting the drug out of reach with a tier-three prior authorization requirement, but Barclays analyst Anthony Butler wrote he expects patients will end up trying generics before ending up with Suvorexant. That aside, Butler noted that capturing 10% of the TRx market could bring in annual sales of $900 million, pricing prescriptions at $150 a month.